method of producing a for use in zahnpastengeeigneten di calcium phosphate - dihydrats

摘要

In the process for the preparation of dicalcium phosphate dihydrate having good fluoride (fluorine) compatibility and hydrolytic stability, which effects further thickening which is as low as possible when it is used in toothpastes, by reaction of calcium carbonate suspended in water with an aqueous solution of orthophosphoric acid, precipitation of dimagnesium phosphate trihydrate as stabiliser by reaction of aqueous solutions of a magnesium salt and of orthophosphoric acid in the presence of a basic compound, and also subsequent filtration, drying and milling of the precipitate, there is added to the reaction mixture as further stabiliser from 0.2 to 0.8 % by weight of polyphosphoric acid, calculated on the basis of the dicalcium phosphate dihydrate precipitated in the reaction mixture.